In the forum you posted in, page down a bit. There should be at least one other thread about this that has lot's of good info already in it. This comes up every so often, so I'm sure there are multiple threads about it - but I seem to recall one not too long ago. It should be easy to find. But, generally speaking, it somewhat depends on where you fill up, but at the same time, it can't hurt to add your own.
This is a fantastic article on diesel fuel management, different additives, etc. in the Club Members area, written by Frank Webster. Join CSR and head over there to read it!